Steel 1109-A (Solution annealed)
Temper
AISI/SAE 1109 · UNS G11090
Softest condition for heavy cold forming, heading or deep boring before final heat treatment.
Values for the A condition
Other 1109 tempers and conditions
1109 is listed in 6 conditions; see the grade overview at 1109.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AThis page Solution annealed | Softest condition for heavy cold forming, heading or deep boring before final heat treatment. | 225 | 370 | 30 | 105 HB | — |
Hot rolled | Cheapest form for parts that will be fully machined all over or subsequently carburized. | 235 | 420 | 25 | 121 HB | — |
Normalized | Uniform fine grain and predictable response before carburizing; used on forged or heavily hot-worked blanks. | 250 | 405 | 28 | 116 HB | 11.2 % IACS |
Cold drawn, stress relieved | Pick when parts machined unsymmetrically must stay straight; low-temperature relief removes drawing residual stress with minimal strength loss. | 380 | 455 | 18 | 131 HB | 10.8 % IACS |
Carburized, quenched and tempered | Choose when the machined part needs a hard wear-resistant skin (pins, bushings, small levers) over a tough low-carbon core. | 400 | 620 | 12 | 59 HRC | — |
CDDefault Cold drawn | Standard stocked screw-machine condition: straight, close-tolerance, bright bar with the best chip control and finish. | 415 | 470 | 15 | 137 HB | — |
What is 1109-A?
1109-A is 1109 in the A temper — softest condition for heavy cold forming, heading or deep boring before final heat treatment. 1109-A has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 97% of steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi). 1109-A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). CD is the default condition FabDigit quotes; A is available on request or by drawing note.
Advantages
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 75/100, better than 90% of steel grades
Limitations
- Low strength — 225 MPa (32.6 ksi), worse than 97% of steel grades
1109-A properties
Typical room-temperature values for 1109-A; 10 are specific to this condition. Other listed values are 1109 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1109-A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
1109-A has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 97% of steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1109-A is rated for continuous service to 400°C (752 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
1109-A conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of 1109-A takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
1109-A's machinability is good (62/100, better than 89% of steel grades); weldability fair (40/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1109-A
Is 1109 easy to machine?
Excellent free-cutting behaviour at high speed with light feeds; keep cutting speed up and use sharp tools to avoid the gummy chips typical of very low-carbon resulfurized steel.
Can 1109 be welded?
Not recommended for structural welds — high sulfur promotes hot cracking and porosity; if unavoidable, use low-hydrogen consumables, preheat and expect reduced joint ductility.
Can 1109 be formed, bent or molded?
Moderate cold formability in annealed or hot-rolled condition, but sulfide stringers cause anisotropy — avoid tight transverse bends and severe heading.
What surface finishes work on 1109?
No corrosion resistance as-machined: specify zinc or nickel plating, black oxide, phosphate-and-oil; inclusions can leave micro-pits after polishing or plating.
1109 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.08 – 0.13 | 0.1 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.04 | 0.02 |
| Sresulfurized for machinability | 0.08 – 0.13 | 0.1 |
| Fe | balance | — |
1109-A — frequently asked
What is 1109-A used for?
1109-A is typically used for small fasteners, pins and light shafts. In short: free-cutting low-carbon bar; machinability score 72; not for structural welds.
What is the yield strength of 1109-A?
1109-A has a typical yield strength of 225 MPa (32.6 ksi) and a tensile strength of 370 MPa (53.7 ksi) — weaker than 97% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1109-A easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Excellent free-cutting behaviour at high speed with light feeds; keep cutting speed up and use sharp tools to avoid the gummy chips typical of very low-carbon resulfurized steel.
Can 1109-A be welded?
With care — weldability is rated fair (40/100). Not recommended for structural welds — high sulfur promotes hot cracking and porosity; if unavoidable, use low-hydrogen consumables, preheat and expect reduced joint ductility.
What surface finishes work on 1109-A?
No corrosion resistance as-machined: specify zinc or nickel plating, black oxide, phosphate-and-oil; inclusions can leave micro-pits after polishing or plating.
Can 1109-A be formed, bent or molded?
Moderate cold formability in annealed or hot-rolled condition, but sulfide stringers cause anisotropy — avoid tight transverse bends and severe heading.
What is the maximum service temperature of 1109-A?
1109-A is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1109-CD and 1109-A?
CD is the default condition — standard stocked screw-machine condition: straight, close-tolerance, bright bar with the best chip control and finish. A: softest condition for heavy cold forming, heading or deep boring before final heat treatment. Yield strength is 415 MPa in CD versus 225 MPa in A.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A108 / A29 — Steel Bars, Carbon and Alloy, Cold-Finished and Hot-Wrought — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.